Using a full service broker with a large account is bad. Using one for a small account is fatal. ML will charge you a fee to switch, but you'll recover the costs within a trade or three.

I use and recommend Scottrade. Go to www.scottrade.com, find their New IRA and IRA Account Transfer froms, print and fill them out (leave the Acct# blank on the Transfer form; you don't have one yet), and mail them to your local Scottrade office with a copy of your latest ML statement.